The ability to perceive and integrate multimodal information is fundamental to perception, cognition, and action. How the individual sensory modalities relate to one another and how their functions are integrated during early development have received increasing research attention in psychology, psychobiology, and the neurosciences. Studies that manipulate the amount, type, and timing of sensory experience during prenatal and early postnatal development are difficult to undertake with human fetuses and infants and a comparative approach utilizing animal embryos and infants offers a useful step in experimentally examining these important topics. Evidence derived from avian and mammalian species has consistently demonstrated that there are differential effects of unimodal and multimodal stimulation on neural, physiological, and behavioral responsiveness during early development. The basis and mechanisms for these effects remain relatively unexplored. The primary goals of this proposed research are to study how unimodal and multimodal sensory experience serves to maintain, facilitate, or interfere with the usual course of intersensory development and to determine the role of intersensory redundancy in guiding and constraining early attentional, perceptual, and learning abilities. Behavioral and physiological evidence obtained from quail embryos and infants in my lab has suggested that the spatially coordinated and temporally synchronous presentation of the same information across two or more senses (intersensory redundancy) can selectively recruit attention and facilitate perceptual learning during the perinatal period. This competing continuation proposal is designed to further explore this facilitative effect of intersensory redundancy and its implications for unimodal and multimodal functioning. Five Specific Aims will focus on the effects of redundancy on (1) selective attention, (2) generalization of learning, (3) memory, (4) behavioral and physiological arousal, and (5) sensitivity to temporal and spatial properties of multimodal stimulation. This program of research will contribute to a better understanding of the complex relationship between prenatal and postnatal ontogeny by providing a core of basic behavioral and physiological data on the arousal, attentional, and experiential processes that contribute to the emergence and maintenance of intersensory perception.